"We have to find officers until the army arrives and we don't know where we are going to find them from," said Chris Jones, secretary of the federation, told the paper.

The Guardian obtained an email G4S sent to National Association of Retired Police Officers asking for help.

"G4S Policing Solutions are currently and urgently recruiting for extra support for the Olympics. These are immediate starts with this Tuesday, Wednesday, Thursday and Friday available. We require ex-police officers ideally with some level of security clearance and with a Security Industry Association [accreditation], however neither is compulsory."

The paper reports several detailed incidents:

Robert Brown, a former police sergeant, told the Guardian that he pulled out of the recruitment process for the Games after seeing it close at hand. He said: "They were trying to process hundreds of people and we had to fill out endless forms. It was totally chaotic and it was obvious to me that this was being done too quickly and too late."

Another G4S trainee, an ex-policeman, described the process as "an utter farce"He added: "There were people who couldn't spell their own name. The staff were having to help them. Most people hadn't filled in their application forms correctly. Some didn't know what references were and others said they didn't have anyone who could act as a referee. The G4S people were having to prompt them, saying things like "what about your uncle?"

Tim Steward, a former prison officer, said he was recruited by G4S in March as a team leader but said he would not be working at the Games because of a series of blunders.

Steward said he provided documentation for vetting but G4S had said it did not have the information on record and so closed his file. The security firm then offered him a training session at short notice, which he could not attend, but it did not offer an alternative.

A recruit who was interviewed in March and completed training last month, said: "There are people like me that are vetted and trained in security and would be happy to work, but can't. Some of the classes were of around 200 in size with only two trainers accommodating the training for a class of this size.

"I am yet to hear from G4S regarding my screening, accreditation, uniform or even a rough start date. I know many people also who will be commencing work on 27 July who have had absolutely no scheduled on-site training. They are simply being chucked into their role on x-ray machines, public screening areas and even athlete screening areas."

Another guard who has been trained as an x-ray operator, complained that he was unable to get through to G4S to find out when and where he was meant to be working, and was once left on hold on the phone for 38 minutes.

One student applicant said he had already spent £650 on travel and hotel bills to attend training and was now worried that, because he had not received any accreditation or rota from G4S, he might not be given the shifts that would enable him to cover those costs. He said he had expected to earn about £2,000 over the period of the Games.

"They've placed me in Manchester and I want to work in London," wrote Glenn Roseman. "Some idiot has changed my location, I'm never going to get any work now."

Christian Smith complained: "I did the training course, passed, and got my own security industry association licence, only to fail G4S vetting. Two days after I got their letter, they rang me, and asked me what days I could work."

Rickie Hill reported that he had been sent someone else's schedule.

Billy Edmunds said that he had been told on the telephone that he was to work four day shifts at the ExCel Centre, only to find when he checked the system later that he had been allocated three night shifts at a different location which he could not attend. "I give up," he said. "Thanks for wasting my time for eight months G4S."

And what does G4S say about all of this? A G4S rep told The Guardian:

"We are unable to respond to the specific questions you raise because to do so would involve pulling staff who are working hard to mobilise the 2012 workforce, off the work they are doing. We will enquire into the claims that are made and we take very seriously any allegation of poor standards on our part."

Follow me on Twitter @johnmclarkejr or e-mail me at johnmclarkejr@gmail.com